• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1962-1969
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint is increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation of the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated core noise reduction techniques to develope a low noise transformer. The techniques to reduce core noise of the transformer are application of high permeability grain oriented silicon sheets, decrease of magnetic flux density of core, application of 6step-lap core stacking method, improvement of core binding method(binding addition, band fixing) and application of rubber damper in oder to reduce transmission of core vibration, etc.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2174-2182
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• 2013

This paper analyzed the PHY technology of IEEE 802.15.7 which is a technology trend and international standard of the LED-based VLC communication system. Also, the study analyzed the complexity of the system as well as the reception performance in a visible light wireless channel environment by analyzing detailed technology of PHY I mode and designing the RS code and block interleaver. According to the result, concerning PHY I which is operated in a single mode, it was confirmed that the complexity in designing the system was higher compared with an environment of the transmission of a short massage. Also it was confirmed that in a multi-path visible light channel environment, the reception SNR=1.5dB was required additionally.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.137-143
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• 2015

This paper presents the intra capacitance modeling based on the winding method and section bobbin for CM choke capable of EMI attenuation of broad bands from lower to higher frequency bands and high frequency type common-mode choke capable of EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. The case of high frequency type CM choke can be explained by the parasitic capacitance of three types of CM choke. The winding method of section bobbin type is smaller than the others. The first resonant frequency of the proposed CM choke tends to increase as the parasitic capacitance becomes small and its impedance characteristics improved performance as the first resonant frequency increases. The CM chokes of the proposed section bobbin type shows that in the future, the method may have practical use in LED/LCD-TV SMPS and in several applications, such as LED lighting, adapters, and so on.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.308-309
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• 2011

최근 PDP와 LCD등의 FPD용(用) 전원 시스템에 고효율화, 고밀도화 및 Slim화를 위한 전원 회로 기술이 요구됨에 따라 이를 실현하기 위해서는 전원 회로를 구성하는 각 컨버터의 최적 Topology 확보뿐만 아니라, 전원 회로에 사용되는 부품들에 대한 차별화된 핵심 부품 기술 확보가 필수적이다. 이러한 요구에 부합하기 위해서 FPD용(用) 전원에 적용되는 자성부품구조도 기존의 성능을 유지하면서 박형화, 저비용화 및 자동 권선화를 구현할 수 있는 방안에 대한 연구가 필요하다. 본 논문에서는 LED-TV용 전원장치의 EMI Filter부의 개발사례 및 특히 EMI Filter부의 대책부품 중에 자동권선형 공통모드 초크의 개발동향 및 사례에 대해서 소개하고자 한다.

• Journal of Power System Engineering
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• v.19 no.1
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• pp.76-82
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• 2015

An analysis model is developed using a commercial software 'simulationX' for designing hydraulic-pneumatic system of heave compensator for offshore drilling operations. Reliability verification of the analysis model for the test equipment of 1/5 scale compensator was conducted by comparing test results and simulation results. An analysis of full scale heave compensator is developed on the basis of verified a model. Then, the results of simulation were analyzed to obtain following conclusion. The displacement of crown block about excitation input amplitude (${\pm}3,000mm$) of the steward platform using a 'simulationX' is attenuated under ${\pm}35mm$, and the compensation rate is 98.7%. In this study, goal of a compensation rate is more than 95%. The previously results are satisfied with the objectives of compensation rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1759-1766
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint has been increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation from the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated tank noise reduction techniques to develope a low noise transformer. According to the mode analysis of transformer tank, we found out characteristics and locations of noise on the tank, and it's nature vibration was also analysed. On the basis of these analysis, reinforcement equipment was installed around transformer tank, and ellipse shape tank was changed to round shape tank. The effect of noise reduction was evaluated using noise generation source.

• The Korean Journal of Cytopathology
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• v.15 no.2
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• pp.120-125
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• 2004

Ewing's sarcoma (ES)/PNET is common in both axial and appendicular skeletons, but is extremely rare in the talus. Here, we report a case of ES/PNET of the left talus in a 29-year-old male patient diagnosed by fine needle aspiration cytology, and review the literature on similar cases. The cytological smears were composed of individually dispersed small round cells and occasional clusters of loosely cohesive cells. The tumor cells were fragile, frequently exhibiting naked nuclei. Two distinct types of cells were observed. The light (chief) cells displayed round or slightly oval nuclei with frequent indentations, generally inconspicuous nucleoli, and a thin rim of cytoplasm, which sometimes harbored small vacuoles. The dark cells were smaller, displaying scanty cytoplasm with dense hyperchromatic nuclei, intermixed with chief cells, and often manifesting as small molded groups. However, no significant nuclear pleomorphisms or mitoses were noted. Tumor cells in the ceil block revealed positive cytoplasmic glycogen, as determined by a PAS stain with diastase control, and also exhibited positive immunoreactivity for CD99.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3607-3623
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• 2014

The increasing demand in promoting cloud computing in either business or other areas requires more security of a cloud storage system. Traditional cloud storage systems fail to protect data integrity information (DII), when the interactive messages between the client and the data storage server are sniffed. To protect DII and support public verifiability, we propose a data integrity verification scheme by deploying a designated confirmer signature DCS as a building block. The DCS scheme strikes the balance between public verifiable signatures and zero-knowledge proofs which can address disputes between the cloud storage server and any user, whoever acting as a malicious player during the two-round verification. In addition, our verification scheme remains blockless and stateless, which is important in conducting a secure and efficient cryptosystem. We perform security analysis and performance evaluation on our scheme, and compared with the existing schemes, the results show that our scheme is more secure and efficient.

• Architectural research
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• v.7 no.1
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• pp.39-48
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• 2005

Main objective of this research is to evaluate performance of high-strength concrete (HSC) columns for ductility and strength. Eight one-third scale columns with compressive strength of 69 MPa were subjected to a constant axial load corresponding to 30 % of the column axial load capacity and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement (${\rho}_s=1.58$, 2.25 %), tie configuration (Type H, Type C and Type D) and tie yield strength ($f_{yh}=549$ and 779 MPa). Test results show that the flexural strength of every column exceeds the calculated flexural capacity based on the equivalent concrete stress block used in the current design code. Columns with 42 % higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour, showing a displacement ductility factor (${\mu}_{{\Delta}u}$) of 3.69 to 4.85, and a curvature ductility factor (${\mu}_{{\varphi}u}$) of over 10.0. With an axial load of 30 % of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 549 MPa.

• Journal of Animal Science and Technology
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• v.61 no.6
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• pp.352-358
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• 2019

The supplementation effects of sea tangle powders were determined for the meat quality in Korean native black goats. A total 90 castrated male black goats at 3-month age were divided into 3 dietary treatment groups: control (basal diet + mineral block), T1 (0.3% sea tangle feeding with the basal diet), T2 (0.9% sea tangle feeding with the basal diet). At 9-months feeding, 10 goats per treatment group were slaughtered, and the longissimus dorsi muscle samples were vacuum-packed, and subsequently analyzed for physicochemical evaluations. Analysis revealed decrease in the shear force and TBARS values of meat in the sea tangle dietary groups (p < 0.05). The T2 group exhibited increased levels of unsaturated fatty acids such as C16:1, C18:1, C18:2, and C20:4 (p < 0.05). The content of free amino acids with desirable taste such as aspartic acid, glutamic acid, glycine, histidine, and serine were higher in T2, whereas alanine content was higher in both sea tangle dietary groups, as compared to control (p < 0.05). These data indicate that feeding dietary sea tangle as an alternative mineral source results in an improvement in the physicochemical profiles of goat meat.